Question about Standard (CRT) Televisions

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Visible scan lines

The scan lines of my sony tv (KV29C5A) are visible on the screen (very faint). Can anyone help me find the source of this problem?

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  • nightbat Apr 01, 2008

    The flayback voltage controler is not located on the transformer. Only the focus adjust is to be found there.

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  • Master
  • 6,966 Answers

Hi,

Two possible reasons/solutions why:
1. one or more of your color drive transistors is/are faulty. These are the 3 transistors normally heatsinked in a separate squarish PCB connected at the rear end of the picture tube (CRT). If one or more is shorted, open is leak, then the video display would have faint re-trace lines. other indicators include too bright, unusual color;
2. the screen voltage from the flyback transformer (FBT) is a bit high. This is adjustable and the control is normally at the FBT itself (towards the rear). There is another control present for the focus.

Of course the usual safety precautions applying when working with live sets or electronics with high voltage and possible residual power (in the capacitors).

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Posted on Mar 19, 2008

  • Louie  Role
    Louie Role Apr 03, 2008

    Hi again,

    Appreciate the postback. If your Sony KV29C5A is of the FE-1 chassis, the G2 voltage controller
    is in the C board. The C board is the squarish board at the very rear
    of the CRT. Adjustment could be made on RV701. If no amount of
    adjustment would make the flyback lines disappear, you need to check
    R722 (680K). In some instances it could also be any of R709 (330K) or
    R718 (33K) or R724 (470K).

    Cheers.

  • Louie  Role
    Louie Role Apr 03, 2008

    A friendly reminder, you will be working probably on a live set and
    very near the high voltage section. The G2 alone carries nearly 1KV,
    please exercise extreme caution and safety practices/procedures when
    performing any of the indicated corrective measures.

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Hi again,

If your Sony KV29C5A is of the FE-1 chassis, the G2 voltage controller is in the C board. The C board is the squarish board at the very rear of the CRT. Adjustment could be made on RV701. If no amount of adjustment would make the flyback lines disappear, you need to check R722 (680K). In some instances it could also be any of R709 (330K) or R718 (33K) or R724 (470K).

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

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